Effect Of Low Level Laser Therapy On Tooth-related Pain And Somatosensory Function Evoked By Orthodontic Treatment

Aims: Low-level-laser therapy(LLLT)may have an effect on the pain associated with orthodontic treatment.The study was to evaluate the effect of LLLT on pain and somatosensory sensitization induced by orthodontic treatment.Methods: Forty individuals(12 to 33 years old,mean ± SD: 20.8 ± 5.9 years)scheduled to receive orthodontic treatment were randomly divided into a laser group(LG)or a placebo group(PG)(1:1).LG received LLLT(810-nm gallium-aluminum-arsenic diode laser on continuous mode with power set at 400 m W,2 J/ cm2)at 0 h,2 h,24 h,4 days,7days after treatment and PG received inactive treatment at the same time points.In both groups the non-treated side served as a control.Numerical rating scale(NRS)of pain,pressure pain thresholds(PPT),cold detection thresholds(CDT),warmth detection thresholds(WDT),cold pain thresholds(CPT)and heat pain thresholds(HPT)were tested on both sides,at the gingiva and tooth of the canine and hand.The data were analyzed by repeated measures analysis of variance(ANOVA).Results: NRS pain scores were significantly lower in the LG group(P=0.01).The CDT,CPT,WDT,HPT,PPT at the gingiva and PPT at the canine tooth were significantly less sensitive on the treatment side of the LG compared with the PG(P<0.033).The testedparameters also showed significantly less sensitivity on the non-treatment side of the LG compared to the PG(P<0.043).There were no differences between groups for any QST(quantitative sensory testing)measures of the hand.Conclusions:Application of LLLT appears to reduce pain and sensitivity of the tooth and gingiva associated with orthodontic treatment and may have contralateral effects within the trigeminal system but no generalized QST effects.Thus,the present study indicated the significant analgesia effect of LLLT application during orthodontic treatment.Further clinical applications are suggested.